The major hypothesis to be investigated is that linguistic intuitions, such as are involved in judgments of synonymy, grammaticality, anomaly and ambiguity, emerge in the child between the ages of four and eight years. Further, such intuitions are hypothesized to emerge later than, and independent of the child's ability to understand and produce the sentences involved. The emergence of linguistic intuitions is hypothesized to reflect the same underlying changes in the child's cognitive abilities as underly the emergence of Piaget's concrete operations. Finally, it is hypothesized that this underlying change is a long-term result of the functional reorganization of the child's brain, as reflected in lateralization language processing. We propose to explore experimentally the emergence of a variety of linguistic intuitions and, in the course of such experimentation, to develop tasks suitable for evaluating linguistic intuitions and comprehension in children. We propose also to develop an improved dichotic listening task for assessing the onset of lateral asymmetry of speech processing. In addition, we propose to perform a cross-sectional study of children between the ages of four and eight years which will examine the relationships between the emergence of linguistic intuitions, standard measures of the emergence of concrete operational thinking and our dichotic listening task. Should the results of the cross-sectional study prove sufficiently promising, we intend to propose a later longitudinal study of the same tasks and age range, based on assumptions about the temporal lag in mastery of different kinds of tasks. Such a longitudinal study will involve a separate research proposal.